1. Technical Field
The present invention relates to a vehicle safety apparatus and, in particular, to an inflator for an inflatable vehicle occupant protection device, such as an air bag.
2. Description of the Prior Art
It is known to inflate a vehicle occupant protection device, such as an air bag, to help protect a vehicle occupant. The air bag is inflated by inflation fluid from an inflator. The air bag is inflated into a position between the vehicle occupant and a portion of the vehicle to help protect the vehicle occupant in the event of a vehicle collision or of a rollover condition of the vehicle.
One type of air bag, known as a side curtain, is inflated between the vehicle occupant and the side structure of the vehicle. It is desirable to maintain a side curtain inflated for a period of seven to ten seconds, in order to help protect the vehicle occupant in the event of a rollover condition of the vehicle.
The present invention is an inflator for inflating an inflatable vehicle occupant protection device. The inflator comprises a storage container, a primary inflation fluid under pressure in a gaseous state in the container, and a secondary inflation fluid under pressure in the container. The container is openable to enable the primary inflation fluid to flow out of the container into the inflatable device to inflate the inflatable device. At least a portion of the secondary inflation fluid is in a non-gaseous state in the container during flow of the primary inflation fluid into the inflatable device. The portion of the secondary inflation fluid in the non-gaseous state thereafter changes to the gaseous state and flows into the inflatable device to maintain the inflatable device in the inflated condition.